1. Field of the Invention
The present invention generally relates to information processing apparatuses and methods of switching operations thereof, and more particularly to an information processing apparatus that is capable of receiving broadcasts and a method of switching operations thereof.
Recently, use of personal computers (PCs) as household appliances has been advanced so that it is desired that television (TV) broadcasts be watched on a PC monitor. However, in the case of using a PC only for watching the TV broadcasts, the function of the PC as a computer is unnecessary. Therefore, a system by which the TV broadcasts can be watched without starting the function of the PC as a computer is demanded.
2. Description of the Related Art
FIG. 1 is a block diagram showing a configuration of a conventional personal computer (PC) 1.
The PC 1 includes a PC main body 11, a monitor part 12 containing a television (TV) tuner 31, and an input device 13 so that TV broadcasts can be watched by means of the PC 1.
The input device 13 is composed of a keyboard or a mouse and used for inputting data or commands to the PC main body 11.
The PC main body 11 includes a central processing unit (CPU) 21, a random access memory (RAM) 22, a read-only memory (ROM) 23, a hard disk drive (HDD) 24, a video output part 25, and an input-output (I/O) control part 26, among which data can be exchanged via an internal bus 27.
The input device 13 is connected to the I/O control part 26, which supplies the data or commands input from the input device 13 to the internal bus 27. The CPU 21, for instance, performs data processing based on a program preinstalled in the HDD 24. The RAM 22, which is used as the working storage of the CPU 21, temporarily contains programs and data. The ROM 23, which contains a start-up program and a variety of setting values, is accessed at the time of starting the PC 1.
Video data processed in the CPU 21 is converted into an RGB signal in the video output part 25 to be supplied to the monitor part 12. The monitor part 12 includes the TV tuner 31, an operation part 32, an RGB converter circuit 33, a changeover switch 34, a display control circuit 35, and an image display part 36. The TV tuner 31 is connected to an antenna terminal Tant1 to which an antenna 41 is connected. Received signals supplied from the antenna 41 to the antenna terminal Tant1 are supplied to the TV tuner 31.
The TV tuner 31 selects the signal of a channel selected by an operation of the operation part 32 from the received signals supplied from the antenna terminal Tant1.
The TV tuner 31 outputs the NTSC (National Television System Committee) video signal of the selected channel. The video signal output from the TV tuner 31 is supplied to the RGB converter circuit 33. The RGB converter circuit 33 converts the NTSC video signal supplied from the TV tuner 31 into an RGB video signal. The video signal converted into the RGB signal in the RGB converter circuit 33 is supplied to the changeover switch 34. The changeover switch 34 selectively outputs one of an RGB video signal supplied from the PC main body 11 and the RGB video signal supplied from the RGB converter circuit 33 in accordance with an operation of the operation part 32.
The output video signal of the changeover switch 34 is supplied to the display control circuit 35. The display control circuit 35 controls the image display part 36 based on the RGB signal supplied from the changeover switch 34. The image display part 36, which is composed of, for instance, a cathode ray tube (CRT) or a liquid crystal display (LCD), is controlled by the display control circuit 35 so as to display an image on a screen in accordance with the RGB video signal supplied from the changeover switch 34.
According to the above-described configuration, TV programs can be watched on the monitor part 12 without starting the PC main body 11 in the PC 1.
FIG. 2 is a block diagram showing a configuration of another conventional PC 50. In FIG. 2, the same elements as those of FIG. 1 are referred to by the same numerals, and a description thereof will be omitted.
The PC 50 includes a PC main body 51 and a monitor part 52 that are different in configuration from the PC main body 11 and the monitor part 12 of the PC 1 of FIG. 1.
The PC main body 51 includes an antenna terminal Tant2. An antenna 71 is connected to the antenna terminal Tant2 so as to supply received TV broadcasting signals thereto. The received signals supplied to the antenna terminal Tant2 are supplied to a TV tuner 61. The TV tuner 61 selectively outputs one of the received signals which one is of a channel selected by the input device 13.
The output received signal of the TV tuner 61 is supplied to a bridge circuit 62.
The bridge circuit 62 converts the signal supplied from the TV tuner 61 into data that is exchangeable through the internal bus 27. The data obtained in the bridge circuit 62 is supplied to the video output part 25.
The video input part 25, which is, for instance, an AGP (accelerated graphics port) compliant video card or a PCI (peripheral component interconnect) bus compliant video card, converts the video data supplied from the TV tuner 61 into an RGB video signal, and supplied the RGB video signal to the monitor part 52. The monitor part 52, which is composed of the display control circuit 35 and the image display part 36, displays an image on a screen on the basis of the video data supplied from the PC main body 51.
According to the above-described configuration, TV programs can be watched on the monitor part 52 in the PC 50. Further, the bridge circuit 62 converts an NTSC video signal received by the TV tuner 61 into data exchangeable through the internal bus 27. Therefore, TV broadcasts can be stored in the HDD 24 in the form of data as converted.
FIG. 3 is a block diagram showing a configuration of another conventional PC 80. In FIG. 3, the same elements as those of FIGS. 1 and 2 are referred to by the same numerals, and a description thereof will be omitted.
The PC 80 is a combination of the PC main body 51 of the PC 50 of FIG. 2 and the monitor part 12 of the PC 1 of FIG. 1. In the PC 80, in the case of watching a TV broadcast without starting the PC main body 51, the TV broadcast is displayed on the screen of the monitor part 12 by operating the operation part 32 of the monitor part 12, converting a TV broadcast signal into an RGB video signal in the RGB converter circuit 33, and controlling the image display part 36 by the display control circuit 35.
Further, in the case of processing the TV broadcast in the PC main body 51, for instance, in the case of storing the TV broadcast in the HDD 24, first, the PC main body 51 is turned on, then, a video signal supplied from the TV tuner 61 is converted into data in the bridge circuit 62, next, the data is supplied to the HDD 24 via the internal bus 27, and the data according to the TV broadcast is stored in the HDD 24. In the case of watching the TV broadcast stored in the HDD 24, the PC main body 51 is started, and the data according to the TV broadcast to be watched is read out from the HDD 24 to be supplied to the video output part 25. The video output part 25 converts the read-out data into an RGB video signal. The RGB video signal is supplied from the video output part 25 to the monitor part 12. In the monitor part 12, the changeover switch 34 is operated in advance by the operation part 32 so that the video signal supplied from the PC main body 51 is supplied to the display control circuit 35. Thereby, the video signal supplied from the PC main body 51 is supplied to the display control circuit 35. The display control circuit 35 controls the image display part 36 in accordance with the video signal supplied from the PC main body 51. An image according to the video signal supplied from the PC main body 51 is displayed on the screen in the image display part 36.
The PC 1 of FIG. 1 has the monitor part 12 containing the TV tuner 31. Therefore, the TV broadcasts can be watched only by turning on the monitor part 12 without turning on the PC main body 11 to start an operating system (OS). However, since a video signal obtained by the TV tuner 31 is not supplied to the PC main body 11, there is a problem that the received video signal is prevented from being stored in the HDD 24 contained in the PC main body 11.
Further, there is another problem that the TV broadcasts are prevented from being watched if the monitor part 12 is replaced by a monitor that does not contain the TV tuner 31.
The PC 50 of FIG. 2 has the TV tuner 61. Connected to the internal bus 27. Therefore, a received TV image can be stored in the HDD 24 housed in the PC main body 51. However, it is always required to turn on the PC main body 51 to watch the television broadcasts on the monitor part 52. Therefore, if the PC main body is turned off, the television broadcasts can be watched only after the OS of the PC main body is started. Moreover, there is a problem of increased power consumption since the PC main body 51 also needs to be turned on in the case of only watching the television broadcasts on the monitor part 52.
The PC 80 of FIG. 3 requires both monitor part 12 and PC main body 51 to contain the TV tuners 31 and 61, respectively. This causes a problem of increased production costs. Further, there is another problem that the function of watching the television broadcasts without turning on the PC main body 51 cannot be used if the monitor part 12 is replaced by a monitor without a built-in TV tuner, such as the monitor part 52.